A vehicle such as an EV (Electric Vehicle) or HEV (Hybrid Electric Vehicle) installs therein a battery unit for supplying electric power to a motor as a drive source. The battery unit is made up of a plurality of battery unit cells which are connected in series. Secondary batteries such as nickel hydrogen batteries or lithium ion batteries are used for the battery cells. The output performance of these secondary batteries depends on temperature, and the output performance is reduced at high temperatures and low temperatures. For example, when a vehicle such as an EV or HEV which installs therein a battery unit made up of secondary batteries is used in a cold region particularly in winter, it is considered that a desired output cannot be obtained because sufficient electric power is not supplied to a motor from the battery unit. Consequently, it is desired that an apparatus for cooling or heating the battery unit is installed in the vehicle.
A heating and cooling apparatus for a vehicle electric unit disclosed in Patent Document 1 includes, as is shown in FIG. 10, a vehicle electrical unit 10 which accommodates a battery 21 and an inverter unit 22 in a main air passage, an induction port 44 from which air within a passenger compartment 6 can be introduced into the main air passage 14, a discharge port 46 from which air flowing through the main air passage 14 can be discharged to the outside of the electrical unit 10, an auxiliary air passage 30 that can be connected to and disconnected from the main air passage 14 and which constitutes a closed circuit when connected to the main air passage 14, and a fan 40 which produces a flow of air in the main air passage 14. When cooling the battery 21, air within the passenger compartment 6 is introduced into the main air passage 14 from the induction port 44 and is then discharged from the discharge port 46 after passing from the battery 21 towards the inverter unit 22 as is shown in FIG. 10A. On the other hand, when heating the battery 21, as is shown in FIG. 10B, air is circulated within a closed circuit 60 which is established by connecting the auxiliary air passage 30 to the main air passage 14.
In this heating and cooling apparatus, when a quantity of air which is equal to or larger than a predetermined flow rate flows in the main air passage 14, a first shutter 51 is closed, while a second shutter 52 is closed. On the other hand, when a quantity of air smaller than the predetermined flow rate flows in the main air passage 14, the first shutter 51 is opened, while the second shutter 52 is closed. In this way, the first shutter 51 and the second shutter 52 are opened and closed by a force based on the flow of air flowing through the main air passage 14, their own weights of the shutters and an elastic force of an elastic member.